JP7471681B2 - Superabsorbent-based suspensions suitable for the moisture-stimulating coating of seeds and a method for coating seeds with the suspensions - Google Patents

Description

A superabsorbent-based suspension and a method for coating seeds with the suspension, particularly suitable for hydrostimulatory coating of seeds. The main use is in agriculture and horticulture. Superabsorbents (SAP = superabsorbent polymers) are used to coat seeds with active ingredients that bind water in the soil in order to increase germination in the absence of water and thus increase crop yields or reduce the frequency of irrigation and reduce water evaporation from the soil, respectively. The ingredients used in combination with SAP improve the flowability between the seeds (reducing friction and wear) and reduce wear and tear of seed drill parts. The suspension can be used as a carrier and depth stabilizer for the active ingredients.

Agricultural production depends, among other things, on the quality of the seeds. The better the seeds (high germination ability, pest resistance, ability to efficiently use individual soil components such as nutrients and water), the higher the chances of a high yield. During germination several metabolic processes take place in the seed. The germination time depends on the seed quality, environmental factors (temperature, presence of water), etc. However, the goal is to achieve optimal germination and defined plant growth even under unfavourable climatic conditions.

In recent years, the problem of insufficient soil moisture at germination has come to the fore. Until now, the problem of seed germination in the absence of moisture was solved by various hydration techniques designed to ensure rapid and optimal germination, to help achieve stable production under suitable economic conditions. For this reason, seeds were treated by various techniques before planting.

An example of a technique that has been used so far to improve seed germination is the so-called "priming" (infiltration). This technique was described by W. Developed by Heydecker et al. in 1974, it involves osmotic control of water supply to seeds using aqueous solutions of water-soluble polymers (polyethylene glycol, sodium polypropionate, etc.) or aqueous salt solutions (W. Heydecker, J. Higgins and R. L. Gulliver, 1973, Nature (London) 246 p.42-44; W. Heydecker, 1974, Univ. Nottingham Sch. Agr. Rep. 1973/1974:50-67; Zuo Weineng et al., 1987, Chinese Science Bulletin 32: 1438).

Another technique is "drum priming". This technique was developed in 1987 by H. R. Rows and consists of spraying the seeds in a rotating drum with a controlled amount of water by weight, without the use of any other medium (GB 2192781 B).

The "solid matrix priming" technique, developed by A. G. Taylor et al. in 1988, uses a powdered material (Agro-Lig) as a medium to control the water supply of seeds (AG Taylor, DS Klein and TH Whitlow, 1988, Scientia Horticulturae 37 (1988) 1-11; US 4912874 A; EP 0309551 B1; WO 88/07318 A1).

Finally, another known technique is known as "matriconditioning". A. The technology developed by Khan et al. in 1990 uses a water-soluble porous material (Micro-Cel E, Zonolite) to control the supply of water to the seeds (A.A Khan, H. Miura, J. Prusinski, I. Ilyas Matrix-conditioning of seeds to improve emergence Proceedings National Symposium on Stand Establishment of Horticultural Crops, Minneapolis, MN Apr. 4-6, 1990).

These techniques moisten the seeds before sowing. However, they also have some drawbacks.

Priming techniques are not suitable for large commercial volumes. Although drum priming technology is simple, the problem lies in the precision mechanical controls that control the amount of water, and also in the technology.

This technique can process seeds with simple, slowly rotating equipment, but the problem lies in the separation of seeds after processing.

In addition to these procedures, there has been recent research into the use of superabsorbents - materials that bind water and then slowly release it to the plant. Two technologies have been developed:
- The first one is to use superabsorbents for seeding the soil, where the polymer is added to the seeding site together with the seed, a process based on which the SAP adheres to the entire substrate (ground). - The second method is to apply the superabsorbent to the seed surface and then sow it.

Patent documents relating to this technology include US 2004077498 A1, US 2008236037 A1, US 2010093535 A1, US 9169164 B2, US 9212245 B2, US 9238774 B2, US 2012258811 A1, US 2014298872 A1, and US 2012277099 A1.

First, the substance was applied to the seeds using a slowly rotating drum, a system of dispensers and dried in an oven (drum priming). The main drawbacks were the higher requirements for the amount of substances used, their uneven distribution and the time of the process.

It is possible to find in the prior art methods in which superabsorbents (SAP) are applied to the seeds in powder form. With various variants, these are either methods in which an adhesive is applied to the seeds and then the (powdered) SAP is added (CN 106471952 A), or methods in which the ability of SAP to adhere to wet surfaces is exploited (US 2012277099 A1), where the SAP is able to very quickly and efficiently absorb water into its structure, thereby attaching itself to the seed surface if it is previously wet. In both cases, the SAP is injected in powder form. In both cases, before distributing the SAP, it is necessary that the seeds are coated with either an adhesive or a substance that contains a certain amount of water and makes the seed surface suitably wet. Thus, in both cases, pretreatment is one additional operation required before distributing the SAP powder.

Both of these cases present some drawbacks. Most of these drawbacks are due to the powder form of SAP. It is not possible to achieve a homogeneous seed coating by injecting SAP powder. Inhomogeneities of the coating are present within one seed, but also when comparing seeds with each other or between batches. A further drawback is that in the case of powdered SAP, the SAP particles do not adhere strongly enough to the seed surface and fall off during storage and sowing activities. This defect increases the SAP consumption and reduces the effectiveness of the dressing process. The SAP particles are also sucked up by the suction device, thus increasing the consumption of SAP that does not come into contact with the seed surface during the dressing process.

SAP particles adhered to a surface by the above methods result in a reduced flowability of the seeds and blockage of the seeds can occur in the sowing equipment or in other operations where the seeds are moved by sieving. At the same time, SAP particles thus fixed are very sensitive to atmospheric moisture, which causes the SAP to stick together and thus the seeds to bind to each other, causing problems in storage, transport and sowing.

A significant drawback is that in the above method, SAP injection alone must be preceded by a seed pretreatment operation to attach the SAP particles to the surface. Such a limitation results in a further decrease in efficiency relative to the time required for pretreatment.

The pretreatment process also affects the different quality of SAP deposition on the surface and the amount of SAP that is deposited, which can have a negative effect if too much SAP or SAP is deposited on the seed, or no effect if too little SAP is deposited on the seed. Different amounts of SAP that are deposited can result in different germination dynamics and subsequent plant development, reducing overall yield.

From a health protection point of view, the described method leads to complications since very small SAP particles enter the air, thus worsening working conditions. SAP particles can be released into the air when the SAP is metered into the seed dressing device, when the treated seeds are discharged and when the treated seeds are subsequently processed.

A technical drawback is the limited use of the seed dressing device. As a priority, the seed dressing device is equipped with an automatic liquid distribution device, but this possibility cannot be used for SAP powder distribution. For the injection of powder material, the seed dressing device needs to be supplemented with an injection device for powder material, which generates additional costs. Application of SAP powder is not possible in seed dressing devices where no powder injection equipment is available. In the described method(s), following the application of SAP, an injection of a singulating substance (Ss) is additionally required, which is also in powder form, requiring an additional powder material injection device and therefore additional costs.

The use of the method in continuous seed dressing equipment is also very problematic or even impossible.

International patent application WO 2005059023 A1 discloses a superabsorbent-based suspension suitable for coating seeds, which comprises a superabsorbent, an adhesive, preferably dispersed or dissolved in an aqueous solution, and a bioactive growth-stimulating additive. The superabsorbent is, for example, a grafted starch copolymer (copolymer backbone) with acrylonitrile, acrylic acid, or acrylamide (graft). The suspension is applied to the seeds in aqueous solution, causing early absorption of water by the superabsorbent during the deposition process, binding and clumping of the individual treated seeds, and clogging of the seeding equipment.

International Patent Application WO 0166668 A2 discloses a composition suitable for seed coating, comprising sodium polyacrylate superabsorbent in an amount of 0.3 wt. %, fertilizer (active ingredient) in an amount of 1.2 wt. %, polyethylene glycol 1450 in an amount of 23.5 wt. %, and ethanol in an amount of 75 wt. %. The composition was applied to the surface of Pickseed (trademark) grass seeds. Another disclosed composition suitable for seed coating comprises sodium polyacrylate superabsorbent in an amount of 4.4 wt. %, fertilizer (active ingredient) in an amount of 15.6 wt. %, polyethylene glycol 1450 in an amount of 30 wt. %, and ethanol in an amount of 50 wt. %. The composition was applied to the surface of rice seeds in a ratio of 3.3:1 (seed:composition). Polyethylene glycol is used in the composition specifically as a lubricant and as a component that provides better mutual compatibility with other polymers, but not as an adhesive or film former. A drawback is also the use of sodium salts of polyacrylic acid, which salinize the soil due to the addition of sodium cations.

Chen, Junwu et al.'s paper (Swelling behaviors of polyacrylate superabsorbent in the mixtures of water and hydrophilic solvents) describes the behavior of a polyacrylate superabsorbent (sodium polyacrylate) in mixtures of water and hydrophilic solvents (e.g., 20%, 40%, and 60% methanol or ethanol). The equilibrium of water absorption by the superabsorbent was determined at 10 minutes and 48 hours, and the authors concluded that the addition of less polar solvents (methanol, ethanol) greatly reduces the absorption capacity of the superabsorbent, especially on short time scales. The paper details only sodium polyacrylate, but not its copolymers, or polyacrylates with other counterions.

The paper by You, Ying-Cai et al. (Synthesis and swelling behavior of crosslinked copolymers of neutralized maleic anhydride with other monomers) describes maleic anhydride/acrylamide copolymers and maleic anhydride/acrylamide/hydroxyethyl methacrylate copolymers with N,N'-methylenebisacrylamide as the crosslinker. The paper also discusses the absorption capacity of these copolymers in alcohol (methanol, ethanol, glycol, glycerol) and water solutions based on the synergistic effect of nonionic functional groups (OH, CONH ₂ ) and ionic functional groups (COOK). An excess of ionic functional groups increases the hydrophilicity and absorption capacity of the copolymer, whereas an excess of nonionic groups reduces the absorption capacity. A clear trend is the decrease in the absorption capacity of the copolymer with increasing alcohol concentration (20%, 40%, and 60%) in the aqueous solution, with ethanol showing the largest decrease in absorption capacity among all the alcohols tested. Due to the two carboxyl groups in one monomer unit, the disadvantages of maleic anhydride are its higher sensitivity to multivalent ions (2+, 3+) present in the soil (mainly Ca2 ⁺ , Mg2 ⁺ , Al3 ⁺ ), stronger intramolecular interactions within one polymer chain, stronger cohesion between different polymer chains, and too strong (even irreversible) fixation of monovalent ions (Na ⁺ , K ⁺ ).

International patent application WO 2013158284 A1 describes a method for reducing dust during sowing with a lubricant component that is applied to the seeds together with a layer of active substance (such as a pesticide). The lubricant component comprises synthetic waxes, waxes of vegetable and/or animal origin (e.g. polypropylene wax) and is characterized in that the seed dust is less than those containing talc or graphite. The lubricant component does not contain superabsorbents that would increase the absorption capacity or even ensure the absorption of water in this layer.

International Patent Application WO 2007103076 A1 discloses seed coating compositions for improving the binding of bioactive ingredients (e.g. insecticides, fungicides) while also improving the flowability of the coated seeds during transportation and sowing. The compositions include adhesives (e.g. polyvinyl acetates or polyacrylates), waxes (e.g. natural, mineral, or synthetic waxes), pigments (e.g. mica coated with titanium dioxide), and stabilizers (suspending agents, water retention agents, biocides). The compositions are wet applied to the seeds in aqueous solutions, which in the case of polyacrylates (although here they act as adhesives) may cause premature absorption of water before sowing in soil.

U.S. Patent Application US 2015267063 A1 discloses seed coating compositions that include antistatic or conductive additives, such as allotropic modifications of carbon (e.g., graphite) or conductive polymers.

The Black et al. paper discloses the use of graphite and talc to improve seed flowability.

Slovak utility model application SK 50110-2016 U1 and Slovak patent application SK 50069-2016 A3 disclose a combination of substances (coating composition) comprising a superabsorbent (polyacrylamide, polyacrylate, or starch copolymer) and an adhesive solution in a mixture of water and ethanol, and preferably a lubricant and a biologically active substance. The superabsorbent is present and applied separately to the seeds in a dry state, which may increase the dustiness, wear of the seed surface, and an uneven surface of the superabsorbent layer. The water-ethanol mixture is adapted to dissolve the additives (30-50% by weight of the adhesive solution), and the above amounts of ethanol (20-40% by weight of the adhesive solution) and water (10-50% by weight of the adhesive solution) may cause premature absorption of water by the superabsorbent during deposition. Furthermore, a method of seed coating with this combination in two steps is described, where first the adhesive solution is applied to the seeds and only in the next step the superabsorbent is in a dry state.

The object of the invention is to provide an environmentally neutral composition suitable for moisture stimulating coating of seeds, ensuring moisture retention in the immediate vicinity of the sown seeds and thus more germination and emergence as well as growth of the plants, especially in dry conditions. Furthermore, the composition should be easy to administer and applicable to the seeds in a more efficient manner than the prior art with regard to meeting stringent agricultural, industrial and safety standards, and should have improved mechanical properties (flowability, dustiness, adhesion) of the coated seeds.

The above-mentioned drawbacks of the prior art are remedied by the present superabsorbent-based suspension suitable for moisture-stimulating coating of seeds, which comprises a superabsorbent, an adhesive dispersed or dissolved in a solution of water and ethanol and/or water and isopropanol, a lubricating additive suitable for improving the flowability of the seeds, and an antistatic additive suitable for removing electric charges.

A superabsorbent, which is a copolymer of acrylate and acrylamide, is included in the range of 25-40 wt. % of the suspension. Preferably, the superabsorbent is a copolymer of potassium acrylate and acrylamide, the potassium acrylate being the result of partial or complete neutralization of the monomer acrylic acid. The individual monomers may form alternating, statistical, block, or graft copolymer structures, and may be in ratios with each other, for example, ranging from 25:75 to 75:25 (acrylate:acrylamide), for example, 25:75, 30:70, 40:60, 50:50, 60:40, 70:30, or 75:25. During seed germination, the superabsorbent gradually decomposes and the acrylamide chains break down into ammonia, which, together with the potassium acrylate salt, provides the seed with important bioelements and nutrients. When sodium salts are used, undesirable soil salinization occurs, which is one of the disadvantages of the prior art.

The suspension further comprises an adhesive which serves to fix the SAP and excipients. The adhesive component also serves as a film-forming component. As adhesives, polyvinyl acetate (PVAc), hydroxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, carboxymethylcellulose, polyvinylpyrrolidone, lignin sulfonate, gum arabic, or sugars may be used. Preferably, the adhesive is polyvinyl acetate, because due to its dense flexible polymer it is able to form a thin and continuous film surrounding the seed surface, thereby not exposing the superabsorbent to moisture in the air. In addition, polyvinyl acetate has a desired level of biodegradability on the seed. Too fast biodegradation of the adhesive layer can occur before sowing, but too slow biodegradation will not allow optimal plant growth. The adhesive is dispersed or dissolved in a solution of water and ethanol and/or water and isopropanol, and the adhesive solution is added in a range of 0.1-8 wt. % of the suspension, 40-70 wt. % of the suspension, 10 ... % ethanol or isopropanol, and 1-10 wt. % adhesive of the suspension.

Another component is a lubricant additive - an aid to improve flowability. The lubricant can be graphite, talc, molybdenum disulfide, polytetrafluoroethylene, polypropylene, or mixtures thereof. Preferably, the lubricant is graphite and/or talc. The suspension contains the lubricant additive in the range of 0.1-15 wt. % of the suspension.

The suspension also includes an antistatic additive in the range of 0.1-5 wt. % of the suspension to remove electrical charge. Preferably, the antistatic additive is flake graphite.

The suspension may also contain active substances to improve the properties of the seeds, which may be nutrients such as fertilizers, vitamins, micronutrients, macronutrients, water retaining agents, wetting agents, pesticides such as insecticides, fungicides, and herbicides, or growth regulators, or biostimulants, in the range of 0.1-10 wt. % of the suspension.

Seeds with this suspension achieve germination and emergence of many crops compared to untreated seeds, direct binding of soil moisture and necessary nutrients to the seed and their subsequent release in times of scarcity. This results in higher hectare yields, higher biomass production, plant pest resistance, and higher survival rate of young plants. This also results in efficiency of the raw materials (SAP or fertilizer) used. The invention encompasses the development of a superabsorbent-based suspension formulation suitable for moisture-stimulating coating of seeds, and a method for coating seeds with this suspension.

Specifically, the present invention adjusts the time required to coat the seeds, reducing the amount of ingredients required and ensuring a more even distribution of the ingredients.

The use of superabsorbents to coat seeds offers the potential to ensure more germination and subsequent growth of the green matter to achieve higher yields. However, superabsorbents must be applied very homogeneously to the seed surface to maximize their effectiveness. Application of superabsorbents to seed coatings is most desirable for plantings in semi-arid and arid regions.

The main innovation of the present invention, which eliminates most of the drawbacks of the prior art, is the use of a liquid continuous phase as a carrier in which the SAP is dispersed, as well as the other components that make up the suspension. The liquid continuous phase, which has a carrier function, is based on ethanol and/or isopropanol and, in addition to its carrier function and the continuous liquid medium, has the task of temporarily blocking the ability of the SAP to absorb water until the volatile components of the suspension have evaporated.

The liquid continuous phase of the suspension allows the entire surface of the seed to be evenly wetted, thus solving the problem of homogeneity of SAP application. Unlike SAP dust particles without a liquid continuous phase, it can efficiently penetrate all uneven areas and wrinkles, while the surface coverage with SAP is uniform at every point of the seed surface. Also, there is homogeneity of coating when comparing individual seeds within a batch and between different batches.

In addition to ensuring an even seed coverage with SAP, reliable control of the application rate of SAP is ensured by varying the SAP concentration in the suspension or by changing the size of the SAP particles in the suspension, respectively. This always ensures that an optimal amount of SAP is applied to the seeds, resulting in uniform germination and emergence dynamics of all seeds of the seed unit and thus ultimately a balanced height. A balanced height is the path to higher yields.

An important aspect of the present invention is the superabsorbent content of 25-40 wt. % of the suspension. Too much superabsorbent on the seed surface leads to smothering of the seed, high water uptake in the immediate vicinity of the seed, thereby preventing sufficient oxygen access and removal of metabolites of the germinated seed. Also, the superabsorbent may not be covered sufficiently with adhesive, and the superabsorbent thus remains exposed, leading to higher hygroscopicity, absorption of moisture in the air, clumping, and binding of dust with individual seeds. Sticky seeds cannot be technically processed, transported, or sieved without problems. In addition, the elevated dust levels do not meet the required dust standards. Conversely, too little amount of superabsorbent on the seed surface leads to moisture deficiency, poor seed germination and plant emergence, especially in dry regions. Low superabsorbent compositions on the seed surface are known in the art and have the disadvantages mentioned above. Non-uniform or variable amounts of superabsorbent deposited on the seed lead to uneven plant growth.

The invention simplifies the seed treatment process since it is not necessary to pre-wet the seeds or apply an adhesive layer on them, but because of the adhesive components (e.g. PVAc) incorporated in the suspension, dry seeds can also be treated directly without pre-treatment. Thus, the time required for seed treatment is saved and the application of the method is expanded. At the same time, the adhesive components also function as film-forming components that smooth the surface of the treated seeds. Thus, the SAP attachment is stable and at the same time the SAP particles become an integral part of the coating without significant protrusion of the SAP particles, eliminating the problem of unstable SAP attachment to the seed surface and also the problem of seed flowability, since the treated seeds do not clog.

After seed treatment, the SAP particles are protected from atmospheric moisture by the film-forming component (e.g., PVAc), thereby eliminating the problem of high sensitivity of SAP to atmospheric moisture and subsequent binding and agglomeration of the treated seeds to each other.

An important aspect of the present invention is the content of the adhesive dispersion or solution, which includes water in the range of 0.1-8 wt. % of the suspension, ethanol and/or isopropanol in the range of 40-70 wt. % of the suspension, and adhesive in the range of 1-10 wt. % of the suspension. Too much adhesive prevents seed germination because the seeds use too much starter nutrients and energy to break through the adhesive layer and not enough remains for further growth, resulting in the death of the plants. If the water concentration is too high and the ethanol concentration is too low, the water is absorbed by the superabsorbents and aggregates are formed, causing the individual seeds to stick together, which is a technical obstacle in seed processing. Too high an ethanol concentration has a negative effect on the seeds due to the biological processes occurring during germination and increases the cost of work safety conditions.

The other components of the suspension, namely talc and flake graphite, also have a beneficial effect on the flowability of the seeds. They also counteract the interbinding and agglomeration of the seeds, especially after the evaporation of the volatile components of the suspension. In addition, graphite, due to its electrical conductivity, reduces the charge that accumulates on the seeds, which arises from the friction of the seeds during the coating process in the seed dressing equipment, but also partly during transportation or in the case of seed transplantation, respectively. The reduction of the charge on the seeds reduces the agglomeration of the seeds.

An important aspect of the present invention is the content of lubricant in the range of 0.1-15 wt. % of the suspension and the content of antistatic additive in the range of 0.1-5 wt. % of the suspension. Too much lubricant additive leads to an incomplete film on the seed surface and more dust. Similarly, too much antistatic additive leads to more dust. Conversely, too little lubricant additive and antistatic additive leads to the formation of aggregates from individual seeds, unacceptable flowability, and the formation of charges that promote the aggregation of seeds into aggregates.

Furthermore, it is important to note that the contents of the individual ingredients are the result of long-term trials (minimum 3-year period) under real conditions (farms, fields with different climatic conditions) and in statistically relevant amounts. The stated contents of ingredients in the suspension are a compromise between optimal seed physiology and optimal processing (suspension preparation, storage, suspension application on seeds, seed drying, flowability).

Injecting SAP in the form of a suspension allows full utilization of the seed dressing equipment, in contrast to current methods where it is not possible to use liquid injection equipment for SAP injection. Injecting SAP in the form of a suspension accelerates the seed treatment process and therefore allows the use of any seed dressing equipment equipped with a liquid injection device, without the need for additional powder injection devices.

Dispensing SAP in the form of a suspension also allows the use of continuous seed dressing equipment.

The liquid continuous phase of the suspension, preferably in an amount of 0.1-10 wt. % of the suspension, may also be used as a carrier for active substances (nutrients, fertilizers, vitamins, microelements, macroelements, minerals, inoculants, water retention agents, pesticides such as insecticides, fungicides, herbicides, biocides, and biopesticides, biofertilizers, growth regulators, or biostimulants) that become part of the seed film formed after evaporation of the volatile components, and may also be used as a fixative. The function of fixing the seed to the substrate (in the ground) is to penetrate the gel formed around the seed and enter the capillaries of the substrate that are in direct contact with the seed. The resulting binding of the seed to the substrate prevents the seed from being pushed out of the soil by the roots, resulting in a slowdown of root growth. Fixation also prevents the seed from being pushed out of the ground or towards the surface. Seed fixation results in faster root growth in the depth direction and thus provides faster access to a water source. Another benefit of this depth stabilization is that the seeds emerge more evenly, which ensures a more even crop. Uniformity in height results in higher yields.

Examples of active agents useful in the present suspensions include, but are not limited to, nutrients, fertilizers, vitamins, trace elements, macro elements, minerals, inoculants, water retention agents, pesticides such as insecticides, fungicides, herbicides, biocides, and biopesticides, biofertilizers, growth regulators, or biostimulants. Nutrients, trace elements, macro elements, and minerals are substances that provide nutrients necessary for plant growth and life and may be selected from the group including nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, boron, copper, iron, chlorine, manganese, molybdenum, and zinc. Fertilizers are plant nutrients and may be selected from the group including nitrogen, phosphorus, and potassium fertilizers, combinations thereof, and organic fertilizers. Biofertilizers are a subset of fertilizers and may include microorganisms of the genera Rhizobium, Azotobacterium, Azospirillum, cyanobacteria, or phosphorus-dissolving bacteria. Vitamins may include vitamin B, vitamin C, and vitamin E. Inoculants are growth-promoting microorganisms and may be selected from the group including Rhizobium, Agrobacterium, and mycorrhizal fungi, for example of the genus Glomeromycota. Water-retaining agents are substances that wet the surface and form so-called conductive zones in the soil, for example surfactants, hydrophilic chains, etc.

Pesticides and insecticides are substances intended to kill insects or other organisms that harm cultivated plants and may be selected from the group including organophosphate pesticides, carbamate pesticides (e.g., thiram), organochlorine pesticides, pyrethroid pesticides, and microbial pesticides. Biopesticides are a subset of pesticides and include microbial biopesticides, such as those of the genera Bacillus, Trichoderma, Agrobacterium, Paecilomyces, Azospirillum, Glomus, Bradyrhizobium, and the like. Microorganisms of the genera Bacillus, Paenibacillus, Rhizobium, and Enterobacter, or metabolites produced by these microorganisms, such as siderophores, bacillibactins, antibiotics, enzymes, plant hormones, lipopeptides, antibacterial polyketides, and bactericidal metabolites. The bactericides are fungicides and moldicides, and may be selected from the group including dimethomorph, mancozeb, tricyclazole, carbendazim, hexaconazole, metalaxyl, benomyl, difenoconazole, propiconazole, kitazine, tebuconazole, copper(I) trihydroxide chloride, copper(I) hydroxide, tridemorph, and propineb. Herbicides are substances intended to kill unwanted vegetation and weeds and may be selected from a group including phenoxy acids, benzoic acids, dinitroanilines, bipyridylium salts, substituted ureas, and arsenic compounds.

Growth regulators include promoters and growth inhibitors, such as auxins, gibberellins, cytokinins (promoters), or abscisic acid (inhibitors). Biostimulants are substances that enhance nutrient efficiency, abiotic stress resistance, and/or crop quality characteristics and may include biofertilizers, growth regulators, inoculants, fulvic acid, humic acid, humins, protein hydrolysates, betaines (e.g., glycine betaine), polyamines, seaweed extracts, and chitosan.

Another very important aspect of the above contents of the individual components of the suspension is the viscosity of the resulting suspension, which influences the wetting of the seed surface with the seed dressing equipment. A suitably selected viscosity allows the utilization of current equipment used for coating or seed treatment. If the viscosity is too high, the pumps and distribution disks of the equipment cannot be used and at the same time the seed surface will not be sufficiently and homogeneously wetted and therefore not coated. The viscosity therefore also influences the amount retained on the seed surface.

As seeds, corn, wheat and other cereal seeds, such as barley, oats, rye, rice, sunflower seeds, rapeseed, sugar beet, soybean, cotton, sorghum, fruit, vegetables, grass and other small seeds, such as beans, peas, lentils, peanuts or rice, can be used. The suspension can also be applied to vegetable and fruit seeds, such as cucumber, tomato, etc.

The object of the present invention is to achieve increased seed germination with SAP in arid and semi-arid regions, to increase the efficiency of SAP deposition on the seed, to increase the SAP uniformity on the seed, to suppress the formation of seed agglomerates during and after the coating process, to improve the flowability in seed transportation and seed application, to use SAP as a carrier for active substances, and to use SAP as a seed depth stabilizer.

The method of coating seeds with a superabsorbent-based suspension according to the invention comprises injecting a suspension comprising a superabsorbent, an adhesive in a solution of water and ethanol and/or water and isopropanol, a lubricant additive and an antistatic additive onto the seeds in a seed dressing device for 5-20 seconds and then releasing the coated seeds from the seed dressing device for 1-10 seconds. The suspension is injected in an amount of 0.1-15 wt. %, preferably 1-10 wt. %, for example 1-5 wt. % or 1-2.5 wt. %, relative to the weight and type of the seed. The amount of suspension injected also depends on the quality of the seed itself, specifically its purity or how dusty it is, respectively. With increasing dust, the injection of the suspension increases for all crops. At the same time, the risk of agglomeration due to dust increases.

In a preferred embodiment of the method for coating seeds, the suspension comprises an active substance as described above.

The invention is further supported by the drawings.

Shown are corn plants with uncoated (left) and coated (right) seeds with the suspension.

Exemplary embodiments The implementation of the present invention will be described by means of examples. The preferred embodiments have no effect of limiting the scope of protection. The singular and plural terms used in the text of the application and in the claims are used interchangeably (e.g. adhesive-adhesives).

Example 1
Table 1 below shows an exemplary composition of the present suspension suitable for the hydrostimulation coating of soybean, sorghum, sugar beet, corn, wheat and rapeseed. The weight percentages are given relative to 100% by weight of the resulting suspension.

Example 2
The method of coating seeds with the suspension includes injecting a suspension containing a copolymer of potassium acrylate and acrylamide, polyvinyl acetate in a solution of water and ethanol, talc, and flake graphite into wheat seeds in a seed dressing device for 10 seconds, followed by releasing the coated wheat seeds from the seed dressing device for 3 seconds. The seeds coated with the suspension are then dried. The result is an evenly coated wheat seed that does not stick to other seeds.

Example 3
The method of coating seeds with this suspension includes injecting a suspension containing a copolymer of potassium acrylate and acrylamide, polyvinyl acetate in a solution of water and ethanol, polypropylene, and flake graphite into corn seeds that have been pre-coated with pesticide (active agent) in a seed dressing device for 16 seconds, and then releasing the coated corn seeds from the seed dressing device for 6 seconds. The seeds coated with the suspension are then dried. The result is an evenly coated corn seed that does not stick to other seeds. In addition, the pesticide layer is protected by a layer of this suspension, reducing the dustiness and wear of individual seeds.

Example 4
The method of coating seeds with the suspension includes injecting the pesticide (active ingredient) into the rapeseed in the seed dressing device, followed immediately by injecting a suspension containing a copolymer of potassium acrylate and acrylamide, polyvinylpyrrolidone in a solution of water and ethanol, talc, and flake graphite into the rapeseed in the seed dressing device for 5 seconds, followed by releasing the coated rapeseed from the seed dressing device for 2 seconds. The seeds coated with the suspension are then dried. The result is a uniformly pesticide-treated and coated rapeseed that does not stick to other seeds. The injection of the pesticide (active substance) and the suspension is also shortened to one step without the need to release the seeds from the seed dressing device.

Example 5
The method of coating seeds with this suspension includes injecting a suspension containing a copolymer of potassium acrylate and acrylamide, polyvinyl acetate in a solution of water and ethanol, talc, flake graphite, and biostimulant (active agent) into soybean seeds in a seed dressing device for 15 seconds, followed by releasing the coated soybean seeds from the seed dressing device for 9 seconds. The suspension-coated seeds are then dried. The result is an evenly biostimulant-treated and coated soybean seed that does not stick to other seeds.

Example 6
Comparison of rapeseed with and without hydrostimulation coating with this suspension at three different test sites in the Czech Republic exposed to different climatic conditions (A-Chlumec nad Cidlinou, B-Opava, C-Luzany u Pfestic) see Table 2. Above average drought conditions were recorded at test site B, which was reflected in the highest yield (19%) compared to the control.

Example 7
The average germination and growth parameters of wheat seeds coated with the suspension compared to control uncoated seeds are shown in Table 3. The suspension had a positive effect on all measured parameters. Seeds coated with the suspension achieved better germination, fewer abnormalities and lesions in the germinated plants, and more above-ground and below-ground biomass.

Example 8
Figure 1 shows corn plants that sprouted from uncoated (left) and coated (right) seeds with the suspension, with the plants sprouting from the coated seeds having a greater amount of biomass, better developed root systems and leaf areas compared to the uncoated plants.

Example 9
The Heubach test is used to determine the amount of free-flowing dust and abrasion particles around treated seeds under defined mechanical stress conditions.The value recommended by the European Seed Treatment Assurance (ESTA) is 0.5 g particles/700,000 seeds.For rapeseed coated with this suspension, a value of 0.1783 g particles/700,000 seeds is reached, which is below the recommended limit.Low seed dust and abrasion are particularly valued in terms of work safety (especially in the case of pesticide treatment, for example) and the efficiency of the entire coating process, i.e. the amount of coating remaining on the seed.

INDUSTRIAL APPLICABILITY The present invention is applicable to the coating of seeds of agricultural and horticultural crops to improve germination, improve the balance of stature, accelerate water access to the roots, stabilize the position of the seeds in the substrate, and increase yields. It is also applicable to the coating of granular and microgranular fertilizers for the purpose of binding and subsequent slow release of nutrients and substances contained therein.

Claims (13)

A superabsorbent-based suspension suitable for moisture-stimulating coating of seeds, comprising a superabsorbent in the form of a copolymer of acrylate and acrylamide, an adhesive dispersed or dissolved in a solution, and a lubricating additive suitable for improving the flowability of the seeds, said suspension comprising said adhesive in the range of 1-10 wt. % of said suspension, said adhesive dispersed or dissolved in a solution of water and ethanol and/or water and isopropanol, said suspension comprising said superabsorbent in the range of 25-40 wt. % of said suspension, a dispersion or solution of said adhesive comprising water in the range of 0.1-8 wt. % of said suspension and ethanol and/or isopropanol in the range of 40-70 wt. % of said suspension, and further comprising said lubricating additive in the range of 0.1-15 wt. % of said suspension, said suspension further comprising an antistatic additive suitable for removing electric charges in the range of 0.1-5 wt. % of said suspension. The suspension of claim 1, characterized in that the superabsorbent is a copolymer of potassium acrylate and acrylamide. The suspension according to claim 1 or 2, characterized in that the adhesive is polyvinyl acetate, hydroxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, carboxymethylcellulose, polyvinylpyrrolidone, lignin sulfonate, gum arabic, or a carbohydrate. The suspension of claim 1, 2, or 3, characterized in that the lubricant additive is graphite, talc, molybdenum disulfide, polytetrafluoroethylene, polypropylene, or mixtures thereof. The suspension of claim 1, 2, 3, or 4, characterized in that the antistatic additive is flake graphite. The suspension according to any one of the preceding claims, characterized in that it comprises an active substance for improving the properties of the seed, the active substance for improving the properties of the seed being selected from the group comprising nutrients, fertilizers, vitamins, micro- and macro-elements, minerals, inoculants, water retention agents, insecticides, fungicides, herbicides, biocides and pesticides such as biopesticides, biofertilizers, growth regulators or biostimulants. The suspension according to claim 6, characterized in that it contains the active substance for improving the properties of the seeds in the range of 0.1 to 10 wt. % of the suspension. 8. The suspension according to any one of claims 1 to 7, characterized in that the coated seeds are maize , wheat , barley, oats, rye, rice, sunflower seeds, rapeseed, sugar beet, soybean, cotton, sorghum, chickpea, fruit, vegetables, grass, beans , peas, lentils, peanuts. 9. A method for coating seeds with a suspension according to claims 1 to 8, characterized in that it comprises applying said suspension comprising a superabsorbent, an adhesive in a solution of water and ethanol and/or water and isopropanol, a lubricant additive and an antistatic additive to said seeds in a seed dressing device for 5 to 20 seconds, followed by releasing the coated seeds from said seed dressing device for 1 to 10 seconds and drying the coated seeds. 10. The method of claim 9, wherein the suspension is applied in an amount of 0.1 to 15 wt. % relative to the weight of the seed. 11. The method according to claim 9 or 10, characterized in that the suspension is applied to the seeds pretreated with at least one active substance from the group comprising nutrients, fertilizers, vitamins, micro- and macro-elements, minerals, inoculants, water retention agents, pesticides, insecticides, herbicides, fungicides, biocides, biopesticides, biofertilizers, growth regulators or biostimulants. 11. The method according to claim 9 or 10, characterized in that it comprises applying an active ingredient to the seeds immediately before application of the suspension, the active ingredient being selected from the group comprising nutrients, fertilizers, vitamins, micro- and macro-elements, minerals, inoculants, water retention agents, pesticides, insecticides, herbicides, fungicides, biocides, biopesticides, biofertilizers, growth regulators or biostimulants. 11. The method according to claim 9 or 10, characterized in that the suspension comprises active substances selected from the group comprising nutrients, fertilizers, vitamins, micro- and macro-elements, minerals, inoculants, water retention agents, pesticides, insecticides, herbicides, fungicides, biocides, biopesticides, biofertilizers, growth regulators or biostimulants.

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